Allow configuration of endpoints using IConfiguration

[seankearney]

In my Azure Function I am heavily using the IConfiguration. More specifically, my connection string to Azure Service Bus is accessed via App Config Service, which in turns gets the value from Key Vault. Ultimately, my actual connection string is available in the IConfiguration. However, based on what I'm seeing it appears that NSB must load the configuration string from an environment variable. See here. Ideally, I'd like to pass you a settings 'key' and the value is fetched from an IConfiguration.

cc @SeanFeldman

[SeanFeldman]

Azure App Config service will not work. Functions documentation says the following:

For function apps running in the Consumption or Premium plans, modifications to configuration values used in triggers can cause scaling errors. Any changes to these properties by the FunctionsStartup class results in a function app startup error.

KeyVault integration works because Functions implements a trick - Function configuration keys are set by the function statically but the values are referencing KeyVault secret URI (with version). Which is also an issue on its own. See this document.

[jenspettersson]

Sorry for using an rather old issue, but we're having a similar issue. We want to use User Secrets when developing due to the fact that we use one Azure Service Bus namespace/instance per developer and want to store the user specific connection string as a user secret.

It fails as the code tries to fetch the connection string from an environment variable, as mentioned by @seankearney.

We could probably just set an environment variable on each developer machine, but we were hoping to be able to utilize the dotnet user-secrets tools instead...

Any ideas?

[seankearney]

@jenspettersson It has been a long time since we tried getting "User Secrets" to work in a function app. Ultimately we gave up on the idea and resorted to using the local.settings.json file, but we added a .gitignore entry to that to prevent it from making its way into source control.

[SeanFeldman]

This issue is primarily focused on providing the connection string to ASB via IConfiguration. This is currently not possible with the link to the documentation here. Also, see this public issue for more context.

Anyone interested in local development using local settings can do so by storing their settings, including ASB connection string, using local.settings.json file, as @seankearney has described.